Fix multimer interface residue detection

[Tanokri02]

Summary

• compare every valid atom pair when detecting inter-chain contacts
• correctly detect contacts between different atom types
• process residue pairs in chunks to limit peak memory usage

Problem

The previous implementation compared only atoms with matching atom, 37 indices, which could miss valid cross-atom interface contacts. Suggested solution in the issue would cause memory issues in large complexes

Validation

• verified a regression case involving different atom indices
• compared results against a full all-atom reference on randomized inputs
• verified the modified file compiles successfully

Test Plan

• Created a test suite for the function for future validation.
  Test with:
  python -m unittest tests.test_data_transforms.TestDataTransforms.test_get_interface_residues -v
  Fixes Bug in interface detection? #539